1. Field of the Invention
The invention relates to printers which are able to execute printing in a printing mode such as a kanji printing mode, an alphanumeric and kana (ANK) printing mode or a multi-parts paper printing mode.
2. Description of Related Art
In this type of printer, printing speed of the print head and the brake pulse width, during a period of time in which power is supplied to a print head in order to inhibit a printing wire from rebounding, are set independently of the printing mode. With this structure, printing has been executed at the same printing speed and with the same brake pulse width regardless of printing mode.
It has been known that to improve printing quality, in a printing mode for executing high density printing, the printing speed must be reduced, or a driving pulse width for forwarding a printing wire and the brake pulse width have to be wide. It has also been known that to improve printing efficiency, in a printing mode for executing low density printing, the printing speed has to be increased or the driving pulse width and the break pulse width have to be narrow. Therefore, when the printing speed, driving pulse width and break pulse width are set to be optimum for printing in a kanji printing mode, for example, and printing is executed in another printing mode which executes higher density printing than the kanji printing mode, the printing speed is too fast for a recovering time of a print head to execute continuous printing. As a result, the printing quality is reduced. While when printing is executed in still another printing mode which executes lower density printing than the kanji printing mode, the printing speed is slower than the speed required for executing printing without reducing printing quality. Further, the driving pulse width and the break pulse width are too wide, thus raising the temperature of the print head so that during printing the print head has to be stopped frequently to cool down. Consequently, the printing efficiency is reduced. Moreover, tearing or severing of printing paper may occur where there is too fast a printing speed and a wide driving pulse.
Therefore in the past, a suppressed, compromise setting value has been used, that is, a printing speed, a driving pulse width and a brake pulse width which are not too bad for any printing mode have been used. The result is problems in some printing modes. Even though a sufficient printing quality can be obtained during high speed printing, printing executed at a low speed does not make the most of the printing efficiency and in some printing modes the printing quality is degraded.